Installs in seconds to replace a worn vinyl sling seat on an 18" or 20" wheelchair. Adjustable drop up to 3 1/2" enables easier chair-walking. May be adjusted to create a "wedge," if desired. Contoured seat improves patient comfort; includes removable, wipe-clean, padded, vinyl cover. For patients at risk for pressure ulcers, a Gel Cushion (#7220F) may be added.